Method of alloying rare metals and articles made therefrom



Patented Dec. 22, 1925'.

UNITE .S T

WILLIAM BENJAM IN GERO. OF EAST ORANGE, NEW JERSEY, AS SIGNOR T0 WESTING- HOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

METHOD OF ALLOYING RARE METALS AND ARTICLES MADE THEREFROM.

1T0 Drawing. Application filed June 14,

To all whom it may concern:

Be it known that I, WILLIAM BENJAMIN GERo, a citizen of the United States, and a resident of East Orange. in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Methods of Alloying Rare Metals and Articles Made Therefrom, of which the following is a specification.

This invention relates to a process of alloying metals whereby corrosiopa'from exposure may be prevented and more particulzirly to facilitate alloying of the rarer meta s.

It is an object of the invention to provide a method of preparing easily corrodible metals so as to practically prevent corrosionpreparatory to or during the alloying proc ess.

It is a further object to provide a method whereby the constituent metals of the desired alloy may be more easily alloyed together.

Another object is to provide a method Ofia; alloying easily oxidizable metals of the rare metal groups that will be readily applicable, eflicient and have no deleterious effect upon the resultant product.

Further objects will become apparept from the description and claims. i

Itis desirable for all practical purposes, to prepare alloys of the rarer metals from, their granular or powdered form owing to the susee tibilityof such metals to corrosion. .while being heatedto the extremely high temperatures at which the metals melt and to the impracticability of maintaining furnaces at the temperatures needed to melt the solid metals from mass form. The rare metal alloys are usually prepared in slug form by compressing the mixed powders, firing and sintering. This process either necessitates the use of some suitable compound of the metal such as the oxide, to which must be added a reducing. agent be fore the metal itself is obtained, or, thd

metal must be used in powdered form, m which case corrosion by exposure to the ele- 1923. Serial No. 645,395.

ments before orduring firing or sintering often takes place. Sintering in a vacuum furnace may be necessary to prevent oxidation.

Certain metals of the group commonly known as rare or refractory metals, such as, uranium, zirconium, tungsten, etc., are peculiarly susceptible to corrosion when ex- ,posed to certain elements while, in a finely divided state. If, however, the powders of the metals be consolidated into a coherent state, as by firing or sintering, corrosion is effectively prevented. I do not attempt to explain thisphenomenon but have found it to be as se tirforth.

The invehtion obviates corrosion of the metals, when in the powdered or granular state, by providing an individual impervious coating for each microscopic grain of the metal and a coating that will not only prevent corrosion for an indefinite period prior to firing and sintering, but also through the critical stages of such treatment. There will be no objectionable dbris left in the metal alloy, which. will be wholly pure, as the coating-l will have been completely volatilized ,anfi-xpelled from between themetal particles priorto their thorough fusion. There will result .a non-porous and comparatively non fragile bar of ,metal or metal alloy, if such be the original form ,of the product. Thecoating may be composed of any gum, wax, resin or like substance, soluble in a suitable solvent, bothof which substance solvent, are completely volatile or leave no harmful residue in the desired metal or in suitable proportions and the metal powders added in proportion to the quality and kind of alloy to be prepared. I have found that anexcellent solution for the purpose may be p'repared by dissolving paraflin in ether in the proportion of 0.12 gram of araflin to 1 .c. c. of ether, which may be ept as a stock solution;

oughly coat all, grains of the tungsten and uranium powders. This proportion may be determined by calculation or experiment as will be readily understood. Sufficient of this stock solution of paraffin-ether. is mixed with alcohol to give a percentage of paraffin to the total weight of metal used, (e. g., tungsten and uranium) of from 0.1% to 1.5% by weight, depending upon the fineness and the amount of uranium used. The uranium or other similar metal is first mixed with alcohol, \then with the solution containing the paraffin. To this mixture is added the tungsten powder, slowly and in small portions, with continual stirring until all has been added.

While it is desirable not to have an excess of the paraffin-ether solution, sufficient should be used to ensure a perfect mixture. The ether and alcohol may then be evaporated from the mixture leaving the parafiin coated metal intimately coagulated in a' compound mixed form.

The coagulated mass thus formed may be pressed into slugs of any desired density and sintered in any desirable manner to form metal bars or slugs for any purpose adaptable. During heating, the paraffin is volatilized and driven off leaving an inti mate mixture of the fine metal particles. If this process be used for alloying two or more metals, an intimate diffusion of one through the other or others takes place and a true solid solution results.

The slugs may be sintered-in a vacuum furnace or other inert environment to insure that there will be no oxidation of the metals during. heat treatment.

It will be noted that all. of the ingredients are protected against oxidation or corrosion throughout the complete process of mixing the metals in powdered form, compressing the powdered metals into slugs and in the sintering thereof into coherent bars.

Moreover, by introducing the powdered metals into a wet solution, a more perfect mixture thereof can be obtained than'dey mechanically mixing the dry'powders. The constituent metals are brought into an intimate association and when the paraflin and solvent are driven off by volatilization a cleansing action of the metal powders takes place. under certain conditions. Each of these results greatly assists alloying.

The method has been described with particular reference to an alloy of two or more of the rare 'or refractory metal groups but as it may be readily practiced to alloy arare or refractory metal with. one of the common orbaser metals, it is not desired that the process be limited. except by the scope of the claims appended.

pressing the coated metal dered metals,

ncense What is claimed is: I

1; The steps in the method of preparing a refractory metal from a comminuted form which comprise, coating the individual particles thereof with a volatile protective coherent state.

'2. The steps in a method of making an alloy with a refractory metal which comprlse, comminuting the constituent metals in a finely divided form, pressing the come minuted metals into a slug and protecting said refractory metal from exposure to the elements during such operation by a protective covering intimate therewith.

3. The method of preparing refractory metals which consists in coating a powdered metal with' a volatile protective'material, owder into a slug and sintering the slug lnto a coherent 4. The method of preparing refractory metals which consists in coating a powdered metal with a volatile protective material, pressing the coated metal owder into a slu and sintering the slug llltO a coherent o y in an inert environment.

'5. The method of protecting powdered agent and sintering said particles into a refractory metal from contamination during fabrication thereof into a coherent body which consists incoating the metal powder with a volatile protective material and sintering the coated metal powder into a compact body in an inert environment.

6. The method of making coherent refractory dered refractory metal with a solid protective coating, a slug'and sintering in an ert with respect thereto.

7. The method 'of making alloys of refractory metals consisting in mixing the alloying metals in powdered form in a solution containing a volatile constituent, evaporating the solvent to produce a coating of the volatile constituent on the powand sintering.

8. The method of making coherent refractory metal bodies consisting in coating the metal in powdered form with parafiin, pressing'the coated metal into a slug and sintering in an environment inert with respect to the metal.

9. The method of protecting powdered refractory metal during fabrication into '00- herent bodies consisting in coating the powderedfmetal with a volatile material impervious to the atmosphere and heat treating said metal in an environment inert with respect thereto to volatilize material and herent form. v

10. The method of protecting powdered refractory metals from corrosion consisting bodies consisting in coating a powconglomerating the metals out saidcoating sinter the metal into acopart, mixing the individual grams of the constituent powders in a solution containing a soluble material solid at ordinary tempera- 10 tures, and. volatilizing the solvent to coat the powders with the solid constituent.

In testimony whereof, I have hereunto subscribed my name this 13th day of June,

WILLIAM BENJAMIN GERO. 

